DOI: 10.1175/JCLI-D-12-00860.1
Scopus记录号: 2-s2.0-84886301167
论文题名: Impact of surface forcing on southern hemisphere atmospheric blocking in the Australia-New Zealand sector
作者: Ummenhofer C.C. ; Mcintosh P.C. ; Pook M.J. ; Risbey J.S.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2013
卷: 26, 期: 21 起始页码: 8476
结束页码: 8494
语种: 英语
Scopus关键词: Atmosphere-ocean interactions
; Atmospheric circulation
; Australia
; Blocking
; General circulation model
; Southern Hemisphere
; Computer simulation
; Thermal gradients
; Tropics
; Oceanography
; atmosphere-hydrosphere interaction
; atmospheric blocking
; atmospheric circulation
; atmospheric general circulation model
; climate forcing
; heating
; sea surface temperature
; Southern Hemisphere
; temperature gradient
; zonal flow
; Australia
; New Zealand
英文摘要: Characteristics of atmospheric blocking in the Southern Hemisphere (SH) are explored in atmospheric general circulation model (AGCM) simulations with the Community Atmosphere Model, version 3, with a particular focus on the Australia-New Zealand sector. Preferred locations of blocking in SH observations and the associated seasonal cycle are well represented in theAGCMsimulations, but the observed magnitude of blocking is underestimated throughout the year, particularly in late winter and spring. This is related to overly zonal flow due to an enhanced meridional pressure gradient in the model, which results in a decreased amplitude of the longwave trough/ridge pattern. A range of AGCM sensitivity experiments explores the effect on SH blocking of tropical heating, midlatitude sea surface temperatures, and land-sea temperature gradients created over the Australian continent during austral winter. The combined effects of tropical heating and extratropical temperature gradients are further explored in a configuration that is favorable for blocking in the Australia-New Zealand sector with warm SST anomalies to the north of Australia, cold to the southwest of Australia, warm to the southeast, and cool Australian land temperatures. The blockingfavorable configuration indicates a significant strengthening of the subtropical jet and a reduction in midlatitude flow, which results from changes in the thermal wind. While these overall changes in mean climate, predominantly forced by the tropical heating, enhance blocking activity, the magnitude of atmospheric blocking compared to observations is still underestimated. The blocking-unfavorable configuration with surface forcing anomalies of opposite sign results in a weakening subtropical jet, enhanced midlatitude flow, and significantly reduced blocking. © 2013 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/51589
Appears in Collections: 气候变化事实与影响
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作者单位: Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia; Centre for Australian Weather and Climate Research, Hobart, TAS, Australia; Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
Recommended Citation:
Ummenhofer C.C.,Mcintosh P.C.,Pook M.J.,et al. Impact of surface forcing on southern hemisphere atmospheric blocking in the Australia-New Zealand sector[J]. Journal of Climate,2013-01-01,26(21)